Computer terminals (such as mobile telephones, laptops, PDAs, BlackBerry®, etc.) are generally equipped with some functions that are used, for example, to check mails, open an instant messaging session, communicate on a Blog, send secure data, etc. Each of these functions is implemented by a specific computer application (or software) integrated in the computer terminal. When a user wants, for example, to connect to an instant messaging service, the computer application of his/her terminal sends a request asking the server to make a connection.
A trivial authentication technique is known wherein, in order to authorize a connection and activate a function, the computer terminal must first send a password directly to the source server or to a gateway server (better known to the persons skilled in the art as “Gateway”) placed between said terminal and said remote server. “Password” with regard to this invention means a secret code possibly associated to the user's identifier. If the password is first sent to the gateway server, the latter analysis said password and, if authenticated, authorizes the connection. Once the connection is made between the computer terminal and the gateway server, the latter connects to the source server such that the information going to or coming from said terminal transits through said gateway server.
If the password is directly sent to the source server, the latter checks the received password and, if the password is authenticated, authorizes the connection with the terminal. As of date, the passwords are generally saved in the computer terminals and in the remote servers or in the gateway servers. The major inconvenience associated with this situation is that a fraudor can easily enter a computer terminal and steal a user's password in order to impersonate him. While the remote servers can generally be hacked with difficulty, the same is not true with the gateway servers. The latter are substantially less protected than the remote servers and in case of an attack, a fraudor can steal all the user passwords in order to impersonate any one of them.
The main technical problem that the invention aims to solve is to improve the safety of connection authorisation procedures between a computer terminal and a source server.